In the remainder of the grant period the investigators will continue their investigation into hormonal control of the differentiated function of the ovary in vitro. The main cell type to be investigated will be the porcine granulosa cell. Special emphasis will be placed on the role of prolactin in regulating these cells but effects of gonadal steroids, gonadotropins, prostaglandins, and polypeptide growth factors will also be evaluated. Studies of the hormonal control of ornithine decarboxylase activity in these cells will continue to be an important aspect of this work.